Vector modulational instability induced by parametric resonance in periodically tapered highly-birefringent optical fibers

TL;DR

This paper investigates how periodic variations in dispersion and nonlinear coefficients induce vector modulational instability in highly birefringent fibers, revealing new unstable regions and the effects of group-index mismatch.

Contribution

It introduces the concept of vector modulational instability caused by parametric resonance in periodically tapered fibers, highlighting the spectral behavior of sidebands and the influence of group-index mismatch.

Findings

Presence of two pairs of vector sidebands for each resonance order

Spectral unbalance between polarization components at nonzero group-index mismatch

Suppression of conventional instability near new unstable regions

Abstract

We study the modulational instability induced by periodic variations of group-velocity dispersion and nonlinear coefficients in a highly birefringent fiber. We observe, for each resonance order, the presence of two pairs of genuine vector type sidebands, which are spectrally unbalanced between the polarization components for nonzero group-index mismatch, and one pair of balanced sidebands emerging and dominating at increasing group-index mismatch. As the conventional modulational instability manifests itself, it is partially suppressed by the proximity of these new unstable regions.